Comparative in vitro antibacterial analysis of different brands of cefixime against clinical isolates of Staphylococcus aureus and Escherichia coli

The objective of this study was to compare the antibacterial activity of standard and different brands of Cefixime, against standard samples and clinical isolates of E. coli and S. aureus collected from different hospitals. Standard samples and isolates of E. coli and S. aureus were separately cultured in Mueller Hinton broth. After the bacterial incubation, 5 ml solution each of standard Cefixime and its different brands were added to the test tubes containing bacterial culture. Cefixime samples were added in the concentration of 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32, 64 and 128μg/ml to separate test tubes. The cultures were again incubated and then the culture samples were analyzed by UV-spectrophotometer, and minimum inhibitory concentrations of all samples were determined. The analysis and interpretation of results were done by single factor ANOVA. An MIC of 0.75μg/ml and 8μg/ml of standard Cefixime was found for standard E. coli and S. aureous respectively. Standard Cefixime and its six selected brands exhibited a higher MIC range for clinical isolates of S. aureus than the clinical isolates of E. coli. Higher MIC values of standard Cefixime and its brands were observed for clinical isolates of E. coli and S. aureus. Higher MIC values for the clinical isolates of E. coli and S. aureus indicated that both the organisms have developed resistance to Cefixime in comparison to standard microorganisms acquired from ATCC.